The present application relates generally to systems for automating repetitive tasks. In particular, the present application relates to the automated handling and sleeving of mail trays for routing bulk mailings and other articles.
The U.S. Postal Service (USPS) allows high volume postal customers to reduce their mailing costs and the delivery time for their mail by presorting, packaging and labeling their mail to reduce handling costs incurred by the USPS. According to the program, customers should sort the mail for a particular zip code destination, and load the sorted mail in a standard size tray. The trays must be sleeved in a cardboard cover. The sleeved tray is weighed to determined postal charges, and tagged with information on the weight, zip code and destination for the USPS. The tagged, sleeved tray is strapped, and finally delivered to the USPS.
The mail is packaged in standard sized mail trays and paperboard sleeves and securely banded. The trays for first and third class mail are in three different sizes designated MM, 4½ inches high, 10½ wide and 24 inches long, and EMM, 6½ high and 11½ wide and 24 inches long. Additionally, Half MM trays are available which have the same height and width as a Full MM tray but are 12 inches long. The sleeves are rectangular cardboard tubes provided in three sizes to accommodate the three standard trays. Customers receive the sleeves as flat, folded blanks. Unfolding a sleeve blank to open it to a tube and inserting a mail tray in the sleeve is a labor intensive operation. Accordingly, there is a need, for an automatic system that can insert a mail tray into a sleeve as part of a larger mail handling system.
One obstacle to an automatic sleeving system relates to the ability of a system to store, feed and form sleeves reliably. The condition of the sleeves is a factor in mail packaging systems. To keep costs low, used sleeves are returned to customers and are reused as long as they are structurally intact. Over its useful lifetime, a sleeve is subject to wear and tear that can cause it to become creased and torn, and the edges and corners become frayed and dog-eared. The condition of a used sleeve makes it difficult for an automatic system to handle the sleeve to reliably obtain it from a supply device, unfold it to a proper shape and position it for inserting of a tray.
One known mail tray sleeving system is the AUTOSLEEVE system available from Carter Control Systems of Frederick, Md. and described in U.S. Pat. No. 5,481,854. This system design has been widely adopted. While this system was an improvement when introduced, it still has practical limitations.
The system described in the '854 patent includes a single, vertical stack of sleeve blanks where only the uppermost of the sleeve blanks in the stack is available for use by the system. Alternatively, two systems may be used in parallel such that trays of each particular size are directed to the sleeving system configured to handle trays of that size. This represents a significant increase in capital investment to operate the system. Also, in practice, the system is advertised as capable of only sleeving 18 mail trays per minute. This cyclic rate is further reduced by the fact that the system must be stopped to replenish the supply of sleeve blanks to the sleever which results in a lower overall throughput.
Accordingly, there is a need for a system capable of sleeving mail trays and capable of handling mail trays of multiple sizes at a single station without the intervention of a human operator. There is a further need for a sleeving system capable of sleeving mail trays at a higher throughput than what is currently achieved. There is yet a further need to provide an automatic sleeving system wherein the supply of sleeve blanks can be replenished without interrupting the operation of the system.